Hi Frank, and welcome to the forum.

You may have better luck with your question on the Solton forum at Yahoogroups.com.

I've not used the sd3 myself but here is a link for how to set up the SD3 for accordion on youtube. The presenter is an engineer for Ketron, very knowledgeable.
http://www.youtube.com/watch?v=4GoqGQGgQXE&playnext=1&list=PL01A239FF324E4AD0&index=54

BTW, the SD3 is now one generation old since the arrival of the Audya 4, so you should be able to get one at a fairly good price.

Good Luck
Don P